1. Technical Field
An area of continual research in the cosmetic product arts is the development of cosmetic compositions especially for non-white pigmented skin that afford to the user enhanced texture, transparency, moisturization, emolliency, and consistency. These features, however, are often abandoned in order to avoid undesirable coloration, such as "whiteness" or "greyness," when cosmetic compositions are applied to such skin. The term "non-white pigmented skin" refers to the tone of human skin, ranging from light yellow to dark brown. Non-white pigmented skin is commonly associated with, for example, Asians, Indians, American Indians, Hispanics and African Americans. Such skin is also associated with individuals whose skin has darkened from exposure to the sun, tanning machines or skin coloring agents. Typically, cosmetics containing either coated or uncoated talcs are opaque to non-white pigmented skin. Such talcs cause undesirable coloration, such as "whiteness" or "greyness," when applied to the surface of such skin. This is due to, inter alia, the limited particle size of these talcs. The average particle size of talc known and used in the art is about 2 .mu.m to about 30 .mu.m (by granulometer). Talcs having such a particle size range are unsuitable for cosmetic compositions for non-white pigmented skin because such talc prevents the natural tone of the skin to emerge freely through it, and consequently the tone of the skin appears unnatural. The term "undesirable coloration" refers to an unnatural appearance of the skin tone when compared to the natural tone of the user's skin. Further, it has been observed that cosmetic compositions currently available to individuals with non-white pigmented skin are scratchy and have an unpleasant effect when applied to the skin. This is due to the chemical agents added, as well as other modifications made, to these cosmetic compositions to eliminate undesirable coloration when cosmetic compositions are applied to non-white pigmented skin. It should be understood that, unless otherwise indicated, the average particle sizes of the talcs disclosed in the specification and the claims appended hereto are set forth in micrometers as measured by a granulometer.
2. Background Of The Prior Art
Undesirable coloration, such as "whiteness" or "greyness," commonly occurs on non-white pigmented skin when it is treated with cosmetic compositions containing talc. Attempts to rectify this problem have been made with little or no success, especially in dealing with skins of darker or richer tones. Such attempts included replacing talc with other components, such as mica, micronized polyethylene, and polymethylmethacrylate. However, it has been observed that these modified cosmetic compositions are inadequate in not only preventing undesirable coloration to the skin, but in skin adhesion and in skin feel. Further, these modified cosmetic compositions have a tendency to dry the skin and to feel coarse when applied.
Talc is one of the primary pigments used in cosmetic compositions. Pigments are those materials which form the base of the cosmetic composition and onto which coloring materials are introduced. Pigments establish the media by which the cosmetic composition is delivered.
However, since talc is exceedingly hydrophilic, it has been known in the art to treat the surface of talc with various agents to make the talc more water repellant (i.e. more hydrophobic) so that the talc will adhere to the skin, and yet repel moisture, thereby extending the wear duration of the talc.
A brochure listing the cosmetic products of Miyoshi Kasei Inc., distributed by U.S. Cosmetics Corp. (hereinafter "Miyoshi Brochure"), provides a comprehensive background on the use of surface treated talcs in the cosmetic industry. For many years, talc has been mixed with various oils and binders in cosmetic compositions. Typically, the talc in these cosmetic compositions was still too hydrophilic, and the resulting compositions would absorb sebum and flow with perspiration when applied to the surface of the skin. As the need to produce cosmetic compositions with greater hydrophobic properties became evident, metal soap was used. However, the surface properties of cosmetic compositions containing talc treated with metal soap were inconsistent, rough and uneven. Attempts to rectify these cosmetic compositions have been made using talc treated with, for example, silicones, amino acids, lecithins and hydrogenated lecithins. See e.g., Miyoshi Brochure; U.S. Pat. No. 4,622,074 (Miyoshi et al.); U.S. Pat. No. 4,863,800 (Miyoshi et al.); U.S. Pat. No. 4,919,922 (Miyoshi et al.); U.S. Pat. No. 5,073,364 (Miyoshi et al.); U.S. Pat. No. 5,073,364 (Giezendanner et al.).
Cosmetic compositions containing silicone treated talc sustain excellent water repellent characteristics and have been widely used in the cosmetic industry. There are, however, drawbacks in using talcs treated with silicone. Specifically, it has been observed that such talcs can be too hydrophobic and the surface of the talc becomes inactive. Skin adhesion and skin feel are often compromised, as silicone treated talcs have a tendency to be dry and coarse to the user's skin. Most significantly, known cosmetic compositions containing such talcs are not suitable for non-white pigmented skin, causing undesirable coloration when applied thereto, such as "whiteness" or "greyness."
Amino acid treated talcs provide "weak acidity" in the make-up powder products without losing water repellent properties. Such treated talcs also exhibit an improved moisturizing feeling in comparison to silicone treated talcs. Amino acid treatment turns the surface of talc weakly acidic, which approximates the pH of the skin and creates a much softer feeling to the user's skin. However, known cosmetics containing amino acid treated talcs are not suitable for non-white pigmented skin, causing undesirable coloration to the surface of such skin when applied thereto.
Lecithin is a glycerol-based phospholipid (similar to a triglyceride which does not contain phosphate), which naturally occurs in cell membranes. It has the general formula CH.sub.2 OR.sub.1 --CH.sub.2 OR.sub.2 --CH.sub.2 OPO.sub.2 OHR.sub.3, where R.sub.1 and R.sub.2 are each fatty acids and R.sub.3 is a small hydrophilic molecule selected from the group consisting of choline, ethanolamine, serine and inositol. Lecithin, which has a hydrophobic tail, comprising the two fatty acid chains (R.sub.1 and R.sub.2) and a hydrophilic head group comprising the phosphate group (--PO.sub.2 O--) and small hydrophilic molecule, possesses emulsifying, wetting and antioxidant properties. Lecithins may be extracted from organic sources such as egg yolk, soybean, corn and rapeseed oil, or may be synthetically prepared.
U.S. Pat. No. 5,073,364 of Giezendanner et al. teaches coating talc with lecithin in pressed powder cosmetics. It has been observed, however, that cosmetic compositions containing talc coated with lecithin generally develop an undesirable yellowish tinge over time. Such cosmetics also display a "draggy" and coarse texture, when applied to the user's skin.
Talcs treated with hydrogenated lecithin provide a smooth feeling to cosmetics and have better moisturizing effects than the amino acid treatments. However, cosmetic product wear is compromised due to the hydrophilic nature of the hydrogenated lecithin and its increased activity as a surfactant. Most significantly, as with known cosmetic compositions containing talc treated with lecithin, it has been observed that cosmetic compositions containing talc treated with hydrogenated lecithin can evidence color and odor change due to instability. Most significantly, it has been observed that known cosmetic compositions containing talc coated with either lecithin or hydrogenated lecithin are not suitable for non-white pigmented skin, causing undesirable coloration to the surface of such skin when applied thereto.
U.S. Pat. No. 4,622,074 of Miyoshi et al. teaches coating talc with a metal salt and a hydrogenated lecithin having an iodine value of less than 30 g/100 g. This iodine value was preferred so that problems with odor and color change can be avoided. See Col. 2, lines 30-34. The iodine value reflects the level of unsaturated fatty acids present in the lecithin used to coat the talc, with values for non-hydrogenated lecithins known to exceed 70 to 90 g/100 g. Cosmetic compositions containing talc coated with lecithin have a tendency to oxidize easily because the fatty acids (R.sub.1 and R.sub.2) in lecithin are mostly unsaturated and emit an unpleasant odor as a result of oxidation. Hydrogenation increases the level of fatty acid saturation in lecithin, up to 30 fold (See Miyoshi Brochure), thereby, as noted above, making it more stable as a useful coating agent for talc in cosmetic compositions.
U.S. Pat. No. 4,863,800 of Miyoshi et al. teaches coating talc with a saturated fatty acid triglyceride having an iodine value of not more than 5 g/100 g. U.S. Pat. No. 4,863,800 of Miyoshi et al. teaches coating of talc with polyolefin carrying--COOR groups (wherein R is hydrogen or metal).
It has been observed, however, that cosmetic compositions containing the coated talcs taught in the above-referenced U.S. patents to Miyoshi do not impart exceptional skin feel nor display an enhanced creamy texture. Most significantly, these cosmetic compositions are not suitable for non-white pigmented skin, causing undesirable coloration to the surface of such skin when applied thereto. This is due, inter alia, to the opacity of the talc, which has an average particle size of about 2 .mu.m to about 7 .mu.m. See Miyoshi Brochure.
Fatty acid esters are occasionally added to cosmetic compositions, typically for use as a surfactant (i.e., wetting agent and emulsifier). In U.S. Pat. No.5,196,186 (Omatsu et al.) and U.S. Pat. No. 5,165,915 (Tokubo et al.), examples of fatty acid esters commonly used for this purpose are provided. The fatty acid esters disclosed in Omatsu et al. and Tokubo et al., however, impart no emolliency, or any other desired attributes to non-white pigmented skin, such as translucency, to the disclosed compositions.
In view of the above, there is a need for a novel class of cosmetic compositions which provide not only beautifying effects to non-white pigmented skin, but also provide enhanced texture, translucency, moisturization, emolliency and consistency. Most significantly, there is also a need for a novel class of cosmetic compositions which afford the aforementioned qualities to non-white pigmented skin, without causing undesirable coloration, such as "whiteness" or "greyness."